Masters Theses

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Chemical changes in a limed and flooded acid sulfate fishpond
Baylon, Carlos C. (University of the Philippines at Los Baños, 1981-10)
Field and laboratory studies were conducted on an acid sulfate soil in Carles, Iloilo with the following objectives: a) to characterize the soils in the pond bottom and along the dikes of an acid sulfate fishpond; b) to follow-up some chemical changes occurring in the flooded acid sulfate ponds, and c) to evaluate the effect of liming on these chemical changes. The pH (1 :1 soil-water) of the air-dried soil samples collected from the pond bottom and along the dikes of the nursery ponds ranged from 2.2 to 4.6. This was significantly correlated with the lime requirement, extractable Al, active Fe and Mn, acetate-soluble sulfate and total sulfur content of the soil. In the field experiment, before lime treatment, the waters of the nursery ponds exhibited decreasing pH with time as well as increasing concentrations of dissolved Al and Fe. The level of Mn in the water was low due to the small amount of active Mn present in the soil. Acidity in the pond waters after a heavy rain was mainly due to the leaching of sulfuric acid from the dikes. Three lime treatments were used in the study: I-lton/ha of lime applied along the dikes and 3 tons/ha on the pond bottom, II - 3 tons/ha of lime on dikes and 1 ton/ha on the pond bottom, III - 4 tons/ha of lime on dikes and no lime on the pond bottom. Treatment II could be considered the most effective way of applying lime since the ponds in this treatment exhibited the highest mean water pH compared to the ponds of the other treatments. Fish mortalities were observed in one of the ponds (NP10 in Treatment III) which may be traceable to the low pH and high Al concentration in the pond water. The applied lime on the dike was not able to control the acidity because it washed down by the rains and covered with eroded soil. The SMP buffer method of determining lime requirement overestimated the lime required to control the acidity of the water in acid sulfate ponds.
The effects of different salinity and organic matter levels on the growth of blue-green algae
Bantillo, Rosario R. (College of Fisheries and Ocean Sciences, University of the Philippines Visayas, 1983-03)
A one-month culture of lab-lab to determine the growth of blue-green algae in three levels of salinity ( 15 ppt = S1, 30 ppt = S2 and 45 ppt S3) and two levels of organic matter (3.4 to 4.4% = OM1 and 6.5 to 7.8% = OM2) was conducted using a twenty-two plastic containers (diameter = 43 cm; height - 49 cm) at the University of the Philippines in the Visayas Brackishwater Aquaculture Center, Leganes, Iloilo. The study utilized a 3 x 2 factorial experiment in completely randomized design with three replicates. Organic matter levels of the soil affected the chemical properties of soil and water (available phosphorus, reactive phosphorus, ammonia-nitrogen and pH). The higher the organic matter level, the higher the pH and the concentrations of ammonia and phosphorus. On the other hand, salinity did not apparently affect the fluctuations in ammonia, phosphorus and pH due to water replenishment to maintain treatment levels of salinity. Earlier rapid growth of blue-green algae commencing on the 3rd to the 15th day was observed at higher organic matter level. While at lower organic matter level, this occurred only on the 18th to the 28th day. Blue-green algae population (units/ml) was observed highest in treatment IV (S1 OM2; 1,262,113) followed by treatments III (S3OM1 ;761,338); II (S2OM1; 514,788); I (S1OM1 ;494,375); V (S2OM2; 413,750); and, the lowest was obtained from treatment VI (S3OM2; 394,275). The relative percentage proportion of blue-green algae in the lab-lab complex showed that it composed 17.7% in treatment IV, 16.86 % in treatment III, 16.64% in treatment II, 15.82% in treatment I, 15.2% in treatment V and 14.9% in treatment VI. These, however, did not significantly vary among treatments. A low correlation coefficient (r) between the population count and the selected parameters: reactive phosphorus, water pH, soil pH and available phosphorus was obtained while a negative correlation was obtained between the population and ammonia-nitrogen. Significantly higher biomass (ash-free dry weight) of lab-lab was obtained in higher organic matter (OM2) and at 45 ppt salinity (S3). The highest biomass (ash-free dry weight) was obtained in treatment VI (S3OM2; 0.160 g/cm2) while the lowest was obtained in treatment I (S1OM1 0.012 g/cm2). The algal count of lab-lab also showed a significant difference in the organic matter levels but no significant difference on the salinity levels. The highest algal count was obtained in treatment V (S2OM2; 6,773,542 units/ml) and the lowest count was obtained in treatment II (S2OM1; 2,328,792 units/ml). However, the primary productivity based on O2 production showed a significantly higher production in the lower organic matter and at higher salinity level (30 ppt.). The highest O2 concentration was obtained in treatment III (S3OM1 ;5.759 ppm) and the lowest was obtained in treatment V (S2OM2; 4.19 ppm).
The effects of different salinity and organic matter levels on the growth of blue-green algae
Bantillo, Rosario R. (University of the Philippines Visayas, 1983-03)
A one-month culture of lab-lab to determine the growth of blue-green algae in three levels of salinity ( 15 ppt = S1, 30 ppt = S2 and 45 ppt S3) and two levels of organic matter (3.4 to 4.4% = OM1 and 6.5 to 7.8% = OM2) was conducted using a twenty-two plastic containers (diameter = 43 cm; height = 49 cm) at the University of the Philippines in the Visayas Brackishwater Aquaculture Center, Leganes, Iloilo. The study utilized a 3 x 2 factorial experiment in completely randomized design with three replicates. Organic matter levels of the soil affected the chemical properties of soil and water (available phosphorus, reactive phosphorus, ammonia-nitrogen and pH). The higher the organic matter level, the higher the pH and the concentrations of ammonia and phosphorus. On the other hand, salinity did not apparently affect the fluctuations in ammonia, phosphorus and pH due to water replenishment to maintain treatment levels of salinity. Earlier rapid growth of blue-green algae commencing on the 3rd to the 15th day was observed at higher organic matter level. While at lower organic matter level, this occurred only on the 18th to the 28th day. Blue-green algae population (units/ml) was observed highest in treatment IV (S1 OM2; 1,262,113) followed by treatments III (S3OM1 761,338); II (S2OM1; 514,788); I (S1 OM1 494,375); V (S2OM2; 413,750); and, the lowest was obtained from treatment VI (S3OM2; 394,275). The relative percentage proportion of blue-green algae in the lab-lab complex showed that it composed 17.7% in treatment IV, 16.86 % in treatment III, 16.64% in treatment II, 15.82% in treatment I, 15.2% in treatment V and 14.9% in treatment VI. These, however, did not significantlyvary among treatments. A low correlation coefficient (r) between the population count and the selected parameters: reactive phosphorus, water pH, soil pH and available phosphorus was obtained while a negative correlation was obtained between the population and ammonia-nitrogen. Significantly higher biomass (ash-free dry weight) of lab-lab was obtained in higher organic matter (OM2) and at 45 ppt salinity (S3). The highest biomass (ash-free dry weight) was obtained in treatment VI (S3OM2; 0.160 g/cm2) while the lowest was obtained in treatment I (S1OM1 0.012 g/cm2). The algal count of lab-lab also showed a significant difference in the organic matter levels but no significant difference on the salinity levels. The highest algal count was obtained in treatment V (S2OM2; 6,773,542 units/ml) and the lowest count was obtained in treatment II (S2 OM1; 2,328,792 units/ml). However, the primary productivity based on O2 production showed a significantly higher production in the lower organic matter and at higher salinity level (30 ppt.). The highest O2 concentration was obtained in treatment III (S3OM1 5.759 ppm) and the lowest was obtained in treatment V (S2 OM2; 4.19 ppm).
A comparative study of the effects of supplementary feeding and artificial substrate on the production of milkfish fingerlings in brackishwater ponds
Adeyemi, Frederick F. (University of the Philippines Visayas, 1983-03)
The growth and survival of milkfish fry in response to supplementary feeding and artificial substrate were evaluated at stocking densities of 75 and 100 fry/m2 for a period of 56 days from August 21 to October 15, 1982. The study was conducted in eighteen 40m2 experimental nursery ponds of the University of the Philippines Brackishwater Aquaculture Centre, Leganes, Iloilo. A 3 x 2 factorial experiment in completely randomized design was used and six treatment combinations between level of inputs (no inputs, supplementary feeding or artificial substrate) and stocking density (75 or 100 fry/m2) were investigated with three replicates per treatment. The best fish growth was obtained in Treatment VI (100 fry/m2 with substrate) with mean final weight and length of 1.59 gm. and 5.36 cm. respectively while Treatment IV (100 fry/m2 without feeding or substrate) gave the poorest fish growth with mean final weight and length of 0.83 gm. and 4.60 cm. respectively. Differences in mean weight and length among treatments were, however, not statistically significant. Mean percentage survival was significantly higher at a stocking density of 75 fry/m2 (82.8%) than at 100 fry/m2 (64.1%) but supplementary feeding or artificial substrate ix did not show any statistically significant effect on survival. At either 75 or 100 fry/m2 stocking density, supplementary feeding gave a numerically higher percentage survival than artificial substrate. Economic analysis revealed that a stocking density of 75 fry/m2 without supplementary feeding or artificial substrate was the most profitable treatment with a return on investment of 39.2%. At a stocking density of 100 fry/ m2, supplementary feeding with rice bran was more profitable than the use of artificial substrate with returns on investment of 22.6% and 9.1% respectively.
Effect of cow and chicken manures on milkfish Chanos chanos (Forsskal) production in brackishwater ponds
Aduma, Ignatius A. (College of Fisheries, University of the Philippines in the Visayas, 1984-05)
A study using chicken and cow manures with basal application rates of 0.5 , 1,2 and 4 tons/ha was conducted. The effect of both manures on some selected physico-chemical properties of the pond soil and water, primary productivity, and milkfish Chanos chanos (Forsskal) yield were compared. Using 8 treatments with 3 replicates each in a completely randomized design, 24 units of 40 m2 ponds were stocked with 20 fingerlings/pond. The fish were cultured from September 22 to December 20, 1983 at the Brackishwater Aquaculture Center of the University of the Philippines in the Visayas College of Fisheries, Leganes, Iloilo, Philippines. The differences among treatments in terms of all physico-chemical parameters monitored were not significant except for the reactive phosphorus. Primary productivity in all treatments was at its peak during the 5th week, after which, it declined gradually apparently due to the combined effects of cloudy weather and low concentration of reactive phosphorus in the pond water. The highest mean net fish yield (680.9 kg/ha) and mean growth rate (1,54 g/day) were obtained in treatment 3 with 1 ton/ha of chicken manure. Treatment 2 (0*5 ton/ha of cow manure) had the lowest mean net fish yield (343.6 kg/ha) and likewise the lowest growth rate (0.80 g/day). The survival in all treatments was high, ranging from 95 to 100%. In general, chicken manure was superior to cow manure, however, fish production from the treatment with 2 tons/ha of cow manure was comparable to that of 2 tons/ha of chicken manure suggesting that cow manure could be used as organic fertilizer in brackish- water ponds for milkfish production.
Quality changes in Tilapia (Oreochromis niloticus) after delayed icing and subsequent storage in ice
Saluan-Abduhasan, Fathma (College of Fisheries, University of the Philippines in the Visayas, 1985-04)
Quality changes in tilapia (Oreochromis niloticus) iced directly on harvesting were compared to those occurring when icing was delayed. Chemical and sensory examinations showed that the shelf life of tilapia was 26 days when iced immediately. 20 days and 16 days with 4 and 8 hours delay, respectively. Fish kept at ambient temperature for 12 hours were rejected after one day in ice. These results suggest that for every hour delay in icing the effective shelf life is reduced by approximately one day up to the 8th hour delay. Total volatile nitrogen values increased with storage time. Likewise, K-value and hypoxanthine values increased as storage time increased. The initial bacterial load ranged from 103- 104 cfu/g of fish with H2S-producers count of less than 100 cfu/g of fish. At rejection, the microbial load was 108~109 cfu/g of fish with HgS-producers count of 106-107 cfu/g. The typical off odours of naturally spoiling fish have been reproduced in blocks of sterile muscle by organisms such as Alteromonas putrefaciens, Pseudomonas sp, pseudomonas maltophilia, Pseudomonas flourescens and pseudomonas stutzeri.
Quality changes in Tilapia (Oreochromis niloticus) after delayed icing and subsequent storage in ice.
Saluan-Abduhasan, Fathma (University of the Philippines Visayas, 1985-04)
Quality changes in tilapia (Oreochromis niloticus) iced directly on harvesting were compared to those occurring when icing was delayed. Chemical and sensory examinations showed that the shelf life of tilapia was 26 days when iced immediately. 20 days and 15 days with 4 and 8 hours delay, respectively.Fish kept at ambient temperature for 12 hours were rejected after one day in ice. These results suggests that for every hour delay in icing the effective shelf life is reduced by approximately one day up to the 8th hour delay. Total volatile nitrogen values increased with storage time. Likewise, K-value and hypoxanthine values increased as storage time increased. The initial bacterial load ranged from 103- 104 cfu/g of fish with H2S-producers count of less than 100 cfu/g of fish. At rejection, the microbial load was 108-109 cfu/g of fish with H2Sproducers count of 106-107 cfu/g. The typical off odours of naturally spoiling fish have been reproduced in blocks of sterile muscle by organisms such as Alteromonas putrefaciens, Pseudomonas sp, Pseudomonas maltophilia, Pseudomonas flourescens and pseudomonas stutzeri.
Effect of utilizing a combination of cow and chicken manures as organic fertilizer in fish pond
Babalola, Julius (College of Fisheries and Ocean Sciences, University of the Philippines Visayas, 1986-03)
An experiment was conducted utilizing twenty 40m2 ponds to investigate the effect of a combination of cow and chicken manures at the following ratios: 1000 kg/ha chicken manure: 3000 kg/ha cow manure; 1000 kg/ha chicken manure: 1000 kg/ha cow manure; 2000 kg/ha chicken manure only; 4000 kg/ha cow manure only; and no manure (control), on some selected physico-chemical properties of the pond, soil and water, primary productivity and production of red tilapia (0. mossambicus x 0. niloticus hybrid) following an (RCBD) - randomized complete block design. Each pond was stocked with 40 fingerlings of red tilapia and cultured for a 90-day period, at the Brackishwater Aquaculture Center of the University of the Philippines in the Visayas, College of Fisheries, Leganes, Iloilo, Philippines. Soil was analyzed for organic matter, phosphorus, nitrogen, pH, using Walkley and Black method, Olsen’s method, Kjehdahl method and pH meter respectively, following standard procedures described in method of soil analysis part II, (Black, 1965). Water oxygen was determined with YSI model 51-B, oxygen meter, salinity with Goldberg’s T/C refractometer pH with pH meter, phosphorus and NH3 - Nitrogen by methods described by Strickland and Parson, 1972. Reactive phosphorus of pond water improved due to the treatments, and supported fish food production leading to the high net fish yield obtained. Primary productivity, an index of living organisms in the pond, was high and suggests that the different treatments supported adequate fish food production. The highest net fish yield (651.03 kg/ha) was recorded in treatment IV (4 tons/ha cow manure only), while the lowest net yield (299.31 kg/ha) was recorded in treatment V (control). Treatments I (1 ton chicken manure and 3 tons cow manure/ ha) and II (1 ton chicken manure and 1 ton cow manure/ha) produced similar net fish yield, 431.97 kg/ha and 431.95 kg/ha, respectively. Treatment III, 2 tons/ha chicken manure only) gave a better net fish yield of 474.82 kg/ha, than treatments I and II. Cow manure can compare with chicken manure as organic fertilizer, in brackish water fish ponds for tilapia. A combination of 1 ton chicken manure and 1 ton cow manure per hectare could be as productive as 2 tons/ha chicken manure only, in tilapia production.
The morphology of the central nervous system of Tilapia Nilotica
Buerano, Corazon C. (University of the Philippines Diliman, Quezon City, 1986-04)
This paper gives an extensive description of the normal morphology of the central nervous system, specifically the brain of Tilapia nilotica stained with. Delafield’s Hematoxylin or Eosin-Hematoxylin. The description covers the 5 major brain areas namely: the telencephalon, diencephalon, mesencephalon, cerebellum and medulla oblongata. Nuclear centers, ventricles, cranial nerves, nerve commissures and sulci found in these areas are identified.
The occurrence, distribution and abundance of larval stages of tunas in Ragay Gulf, Burias Pass, Ticao Pass and waters north of Samar Sea
Abuso, Zenaida V. (University of the Philippines Visayas, 1988-03)
A total of 146 tuna larvae representing a 0.004% share in the total fish larvae catch was collected from Ragay Gulf, Burias Pass, Ticao Pass and waters north of Samar Sea during the sampling period from November 1981 to December 1982. Seven species of tunas were identified and described to species level. Euthynnus affinis. and Thunnus obesus. comprised a highest relative abundance of 24.05% in the larval tuna collection. Auxis thazard and A. rochei were secondly abundant with 16.0% and 14.0% share, respectively. Thunnus albacares, Thunnus alalunga and Katsuwonus pelamis were relatively rare with only 5, 4 and 2,0% share, respectively. The highest abundance of the larvae were observed mainly irr Ragay Gulf in May where warmer temperatures ranging from 26.56°C to 28.9T°C and salinity values from 33.97°/oo to 34.42°/oo prevailed.
The effect of common table salt added in different levels of water salinity as culture medium on growth and survival of prawn larvae Peneus monodon Fabricius
Abeto, Mario N. (College of Fisheries, University of the Philippines in the Visayas, 1989-09)
A study was conducted on the effect of common table salt added in waters of different salinity levels used to determine the survival rate, developmental stage, and carapace length of Penaeus monodon larvae from zoea one to post larva one. The following treatments which were adjusted to 33 ppt by adding varying amount of common table salt were: treatment I (8 ppt + 29 g/l) , treatment II (13 ppt + 23 g/l) , treatment III (18 ppt + 17 g/1), treatment IV (23 ppt + 11 g/1), and treatment V (28 ppt + 5/g) . Natural seawater with salinity of 33 ppt was used as control. Certain key ions like Na+, CL-, Ca2+, and Mg2+ were analyzed in each treatment. A sharp drop of. population in all treatments was recorded in the first 5 days of the zoeal stage. Treatment V gave the highest survival rate (25%) , but not significantly higher than treatment IV (20.5%) and control (18%); however, significantly higher than treatment III (10.5%) and treatment II (6.5%) at P<0.05. None of the larvae survived in treatment I after 5 days. Larvae exposed to treatment V had completed post larva one in 11 days (growth index 7). This was not significantly different, however, from those obtained from the control (growth index 6.6) and treatment IV (growth index 6.3). The lowest growth index value which was significantly lower than treatment V was obtained from treatment II and treatment III (growth index 6.0). During the first sampling, carapace length in treatment I reached 0.47 mm, succeeded by the following treatments: III (0.43 mm) , II (0.42 mm) , and V (0.40 mm). Treatment IV and control gave similar results (0.30 mm). After 2 days, rate of increase of CL had shifted from lower to high ionic concentrations culture media. At the end of the study the following carapace lengths were obtained: 1.2 mm for treatment V, 1.15 mm for control, and 1.08 mm for treatment IV. Values obtained from treatment II (0.94 mm) and treatment III (0.98 mm) were significantly lower than treatment V (1.15 mm). Rearing waters with higher concentrations of K+ and Mg2+ (control, treatments I, and II)showed better growth rate and percent survival than those media with relatively lower concentrations (treatments I, II, and III) . The addition of common table salt to low saline waters, however, did not compensate for the loss of physiologically important ions needed for growth and survival of prawn larvae.
Growth and yield Rabbitfish (Siganus guttatus) reared in river floating net cages at various stocking densities and feeding schemes
Abalos, Rosie S. (University of the Philippines Visayas, 1995-03)
Six treatment combinations consisted of three stocking densities of 50, 100, 200, rabbitfish (Siganus guttatus) per cubic meter (m3) at two feeding schemes of sliding 10, 8, 6, 5% commercial feed of fish biomass (F1) and 5% commercial feed of fish biomass daily with Chaetomorpha linum. "lumut" fed to satiation (F2) were tested to determine the growth and yield of rabbitfish in river floating net cages for 120 days. The F1 at stocking density of 50 fish/m3 and fed commercial feeds daily at sliding (10-8-6-5% BW) feeding scheme registered the highest mean growth of 105.6 g/fish. However, statistical analysis showed no significant difference (P>0.05) in growth among treatments. In terms of production, the F2 at 200 fish/m3 and fed commercial feeds at 5% BW plus "lumut" registered the highest mean production of 18.23 kg/m3 . Production was highly significant (P<0.01) in between stocking densities but not between feeding schemes. Survival (90 - 96%) and mean feed conversion ratios (3.6 - 4.4) were not significantly different (P>0.05) among treatments. Rearing S. guttatus in floating net cage at 200 fish/m fed commercial feeds daily at 5% BW plus "lumut" fed to satiation appeared to give the highest net income of P705.96/m and a benefit-cost-ratio of 1.42.
Comparison of the catching efficiency of the traditional and modified fish corral in Panguil Bay
Acuña, Rodrigo E. (College of Fisheries and Ocean Sciences, University of the Philippines Visayas, 1997-12)
This study was conducted in two fishing sites of fish corral in Panguil Bay namely; Malaubang, Ozamiz City and Maquilao, Tangub City from November 21,1994 to July 10,1995. Two types of fish corral such as traditional and modified were identified. Results showed that average catch per trip was higher in the traditional fish corral (5.1 kg/day) compared to the modified fish corral (4.2 kg/day). The traditional fish corral also have a higher species richness (mean=105 species) against the modified (mean=50 species). About 90% of the catch of the traditional fish corral are commercially important species is significantly higher than the other type (50%). Catches of the traditional and modified fish corral largely consist of shrimps (Metapenaeus ensis: MFC; Penaeus indicus: TFC). Based on the relative density and weight of the total catch, Metapenaeus ensis (mean=222 individuals) is recorded as the most dominant species caught by the modified fish corral while Penaeus indicus (mean=38 individuals) exhibited as a dominant species in the traditional fish corral. Results of the statistical analyses on the data collected on irregular sampling dates show no significant difference on the catches between the traditional and modified. Significant difference is observed on the catches collected during the same sampling dates. Traditional fish corral is more efficient because it has higher catch per trip, species richness and high percentage of commercially important species. Modified fish corral as well, is effective with regards to its catch quantity, however it is inefficient in terms of its catch quality, i.e., of low commercial value.
The effect of sex reversal treatment on the growth and survival of two strains of Nile tilapia (Oreochromis niloticus) and Mossambique tilapia (Oreochromis mossambicus) raised in brackishwater
Badillo, Susan Delos Santos (University of the Philippines Visayas, 2000-08)
A study to determine the effects of sex reversal (SRT) on the growth and survival of two strains of Nile tilapia (Oreochromis niloticus) and Mossambique tilapia (Oreochromis mossambicus) was conducted in four 2m x lm x 1.5m suspended hapa nets in UPV-IA Hatchery and Biology brackishwater fishpond for 75 days. The experimental treatments and codes used in this study were the following, Treatment GGn (GIFT/normal), Treatment GGsrt (GIFT/sex reversal), Treatment MMn (Moss/normal), Treatment MMsrt (Moss/sex reversal), Treatment GEn (GIFT-Egypt/normal) and Treatment GEsrt (GIFT-Egypt/sex reversal). Juvenile fry (average weight 0.0 1g) were subjected to sex reversal treatment by feeding fish diet with methyltestosterone at 60 mg per kg of feed for three weeks in freshwater. After SRT, the fingerlings were nursed in fine mesh net (0.5 mm mesh, 2m x 1m x 1m) for 30 days until the fish attained the weight from 3.0 g to 5.3 g. They were individually tagged by fin clipping method. They were acclimated from 0 ppt to 20 ppt prior to experimental proper. Juvenile fish of 3.40-5.44 g were communally stocked at 25 fish each treatment. Juvenile fish were fed with a commercial feed at 15% of their mean body weight per day from 1-30 days and 10% per day of their mean body weight from day 31-75 days culture period. Within the normal treatments, there was no significant (P>0.05) difference in mean body weights between Treatments GGn and GEn but both are significantly higher (P<0.01) than Treatment MMn. Within the sex reversed treatments, mean body weight in Treatment GGsrt was not significantly (P>0.05) different from Treatment GEsrt, but showed high significant (P<0.01) difference with Treatment MMsrt, similar to the normal treatments. The highest average final biomass of 808.88 g was obtained in Treatment GGsrt followed by Treatment GEsrt (795.58 g) and lowest in treatment MMn (367.63 g). The biomass gain of tilapia within the normal treatments ranged from 282.6 g to 672.95 g. Treatment GGn showed no significant (P>0.05) different from Treatment GEn, but both were significantly higher from Treatment MMn. The same trend was observed within sex reversal treatments. Treatment GGn obtained the highest (589.70%) percentage biomass gain and Treatment MMn (335.01%) was the lowest within the normal treatments. In sex reversal treatment, Treatment GGsrt has no significant difference with Treatment GEsrt, but both showed a high significant difference in Treatment MMsrt. Highest specific growth rate was observed in Treatment GGn (2.62 g day^-1) and lowest in Treatment MMn (1.97 g day^-1). Mean condition factor (MCF) of tilapia was highest in Treatment GGn (1.60), followed by Treatment GEn (1.56) and lowest in Treatment MMsrt (1.17). Within the normal treatments, Treatment GGn and GEn showed no significant difference (P>0.05), but both were significantly higher (P<0.01) than Treatment MMn. Within the SRT treatment, all treatments showed highly significant (P<0.01) difference from each other with highest at Treatment GGsrt and lowest at Treatment MMsrt. Mean survival ranged from 95% to 100%. Highest percent male population was obtained in hormone-treated fish (95-100%) compared to normal treatments (64-71%). Sex reversal treatment did not improve growth and survival of the two strains of Nile tilapia (O. niloticus), but improved the growth of Mossambique tilapia (O. mossambicus) significantly after 75 days under the conditions this experiment was conducted.
Tolerance and behavioral response of Juvenile Siganus guttatus to Abaca Pulp Mill effluent
Bradecina, Raul G. (College of Fisheries and Ocean Sciences, University of the Philippines in the Visayas, 2003-04)
Acute bioassay and avoidance-preference tests were done on juvenile S. guttatus using lethal and sublethal concentrations of Abaca pulp mill effluent to assess the fish tolerance and behavioral response to the toxic stress and determine its effect to the chemoreception of biologically important odors. Acute bioassay response data were analyzed by log-probit method. Behavioral response data were calculated from the mean reaction values of the fish samples in the Y-maze apparatus. Results show the fish has a very narrow resistance to the toxic stress of the effluent with LT50 values of 1.6 h for the highest (100% vv-1) and 37 h for the lowest (10%vv-1) concentrations. The 48 h LC50 was located at 9%vv-1 which indicated the fugacity of the effluent and the sensitivity of the fish to its toxicity. The lowest concentration of the effluent with observed significant effect (LOEC) was located at 10%. The fish showed pronounced and significant discriminating ability at lethal concentration of the effluent. Avoidance reactions of the fish were only observed at 9% vv-1 (lethal) and 0.9 % vv-1 (sublethal) concentrations. The avoidance threshold was found at 0.74 % vv-1. Juvenile S. guttatus has a very narrow acuity to the effluent, which was located at a tenth ofthe mean lethal concentration value. Abaca pulp mill did not mask chemoreception of biologically important odors in juvenile S. guttatus.
Environmental impacts of marine cage farm (Lobster culture) in Van Phong Bay, Khanh Hoa, Vietnam
Du, Hoang Trung O. (University of the Philippines Visayas, 2003-07)
The study carried out two surveys at five sites in lobster cage farming activities, during rainy season (November 2002) and dry season (February 2003). It includes 236measured data on physical and chemical parameters of water quality, 115 data on sediment characteristics, and 30 macrobenthic samples. The results of the study indicate that the lobster cage farming activities are related to the accumulation of organic materials on seabed of the cage farm. The impacts of lobster cage farms on water quality might come directly from the cage farm and indirectly from the release of organic and inorganic matter from sediment bottom which significantly changed depending on the season. This could be seen in the total inorganic nitrogen (TIN) concentration at the bottom, which is higher by 6-10 times during the dry season than that during the rainy season. Moreover, cage farming enriches the water column through the release of nutrient and particulate organic matter and affects the sea bottom with deposition of sediment particles. The study clearly marked variation in organic matter and chlorophyll-a concentrations in sediment. In addition, the particulate organic carbon in water samples also showed the negative impact under the cage. The results of sediment trap exhibited high organic content at stations near the cage (stations 2 and 3) as compared to the station farther the cage and the control site. On the other hand, organic matter in surface sediment was significantly higher under the cage than in the control site. This suggests that accumulation of organic material under and near the cage is highly deposited by particles that come from the cage farm. There were observed changes in benthic community in terms of species, abundance, and biomass. Changes in benthic composition were different between stations near the cage and the control site. This indicates that benthic community patterns were affected under the cage and those near the cage farming activities. Macrobenthic communities were dominated by polychaete species during the two surveys. Polychaetes represented more than 55% of benthic abundance as well as greater than 60% ofthe number of species. This study shows that it may be possible that some polychaete species such as Magelona sp, Myriochelle sp, can be important bio-indicators of heavy organic load in the cage farms. On the other hand, polychaete species Prionospio aficana, Orbinia vietnamensis might be considered as candidate indicator species for detection of organic enrichment in the cage farms. In addition, these can serve as baseline information for future studies to evaluate the environmental impact of cage farm. The relationship and interaction between factors that cause eutrophication is therefore particularly important for future studies.
Nutritional value of fish silage, with Gracilaria Sp. and Abalone Viscera as poultry feed
Patadjai, Andi Besse (University of the Philippines Visayas, 2004-11)
Study on fish silage prepared with , with and without abalone viscera was conducted to evaluate the rate of hydrolysis during the ensiling process. The fish-Gracillaria sp.-abalone viscera silage was further subjected to nutritional value test as poultry feed. Three silage were prepared using 5% propionic acid and formic acid (ratio 1:1) to contain: a) 100% fish by catch (Silage F), b) 70% fish by catch and 30% Gracilaria sp. (Silage FG) and c) 70% fish by catch, 25% Gracilaria sp. and 5% abalone viscera (Silage FGA). These silage were stored for 15 days and stirred daily. Chemical components such as pH, amino nitrogen, polypeptide, and monosaccharide content were determined at regular intervals within the 15-day ensiling period. Isonitrogenous feeds were then formulated to contain fish-Gracillaria sp.- abalone viscera silage Feed (II) and fish silage (Feed III). Nutritional value of these diet (i.e. Feed II and Feed III) were compared with that of commercial feed (Feed I) which was used as the control, based on the growth response of chickens. Results showed that rate of decrease in pH value was sufficiently rapid to stabilize the three silage. Silage F showed significantly higher pH value throughout the ensiling period, compared with Silage FG and Silage FGA. No significant difference (P<0.05) was, however, found between Silage FG and Silage FGA. Results can be attributed to incorporation of Gracilaria sp. in silage production, which provided favorable condition to decrease the pH value. Amino nitrogen content of all silage increased with ensiling time. Silage F exhibited the highest amino nitrogen content during 15 days of ensiling, followed by that of Silage FGA. Although the amino nitrogen content of Silage FGA was higher than that of Silage FG, significant differences (P<0.05) were noted only after 12 days of ensiling. Polypeptide content of all silage decreased after 3 days of ensiling. Silage FGA exhibited the highest polypeptide content after 9 days of ensiling. Monosaccharide content of all silage fluctuated during the ensiling period. However, the highest value was noted with Silage FGA, followed by Silage FG on the 3rd day of ensiling. This could be attributed to the highest polysaccharide hydrolysis rate exhibited by Silage FGA throughout the ensiling period. The best feed conversion ratio (FCR) and protein efficiency ratio (PER) were obtained with chickens given feed containing fish-Gracilaria sp. -abalone viscera silage (Feed II) during the 3-week feeding time. Body weights of chickens given Feed II were significantly higher than those given Feed III until the 3rd week of feeding. Reduction of fish content by as much as 30% and its substitution with 25% of Gracilaria and 5% of abalone viscera in silage (Feed II) gave the same effect on growth rate of chickens as that of silage made up of 100% fish (Feed III), and commercial feed (Feed I) without any mineral deficiency symptoms (e.g. slipped tendon or leg weakness and abnormal feather growth). Fish-Gracilaria .sp.-abalone viscera silage could be used as an ingredient for the production of an acceptable/palatable and nutritious feed for poultry.
Effects of different levels of Pinus tebulaeformis pollen on growth and stress resistance of milkfish fry (Chanos chanos)
Baldove, Analyn B. (University of the Philippines Visayas, 2010-06)
The present study investigated the effects of different inclusion levels of pine pollen from Pinus tabulaeformis Carr. on the growth performance and stress resistance of milkfish fry (Chanos chanos). Milkfish fry with average body weight of 0.02 g were stocked in 15 tanks (40 fish per tank). A control diet (without pine pollen) and four experimental diets were prepared containing different levels of pine pollen at 0 g kg^-1, 1.3 g kg^-1, 2.6 g kg^-1, 3.8 g kg^-1, and 5.1 g kg^-1 was fed to the experimental fish for 60 days. At the termination of the experiment, milkfish were subjected to acute ammonia and high salinity shock test. The result of feeding trial revealed that milkfish fed diets containing different levels of pine pollen stowed significantly higher growth (p < 0.05) in terms of weight gain, specific growth rate, feed conversion ratio, and protein efficiency ratio than the control diet. Survival of the milkfish during the trial were not significantly different among treatments (p > 0.05). Survival rates of milkfish groups exposed to high salinity stock test for 72 h were not significantly different from each other (p > 0.05). In contrast, results of the ammonia stress test revealed that the survival rates of milkfish fed with the diets containing (2.6 to 5.1 g kg^-1) were significantly higher (p <0 .05) than those fed with diets containing 1.3 g kg^-1 and the control diet Optimum dietary PP level was estimated using the quadratic model by using SGR and FCR values and found to be is 2.9 g kg^-1 and 3.0 g kg^-1, respectively. conclusion, pine pollen can be used as a supplement in milkfish diet to enhance growth and stress resistance against environmental stressors like ammonia.
Evaluation of different carbon sources used in the biofloc technology (BFT) culture of Litopenaeus vannamei
Alaban, Leovigildo Rey S. (College of Fisheries and Ocean Sciences, University of the Philippines Visayas, 2011-04)
An evaluation of different carbon sources used in Biofloc technology (BFT) culture of L. vannamei was done. The experiment included five treatments: Control, RB (Rice Bran), Tap (Tapioca), Mol (Molasses) and COMBI (Molasses + Rice Bran). Evaluation of biofloc parameters - Total Suspended Solids (TSS) and Settleable Solids (SS)- showed an increasing trend in treatments with molasses (Mol and COMBI) as the culture progressed. This became significantly different (P < 0.05) in the later phase of the culture. The evaluation of environmental parameters included TAN (Total Ammonia Nitrogen), NO2-N (Nitrite Nitrogen) and Chlorophyll a. In treatments with rice bran (RB and COMBI), TAN showed an increasing trend, becoming significantly different with the rest in the later phase of the culture (P < 0.05), while NO2-N were maintained below toxic levels. Chlorophyll a didn’t show any discernable pattern. The effect on L. vannamei was evaluated based on growth (ABW-Average Body Weight, SGR-Specific Growth Rate and FCR- Feed Conversion Ratio) and yield (Survival and Biomass) parameters. Treatments with rice bran showed faster growth rates compared to the rest (P < 0.05) for most part of the culture period. However, analyses of growth parameters based on harvest data don’t show any significant difference in SGR and final ABW for all treatments. Further, poor water quality in these treatments lead to heavy mortalities which caused FCR and Biomass to be significantly different (P < 0.05) from the rest of the treatments.
Effect of elevated carbon dioxide and phosphorus on nitrogen uptake, lipid content, and growth of Tetraselmis sp.
Ferriols, Victor Marco Emmanuel N. (Institute of Aquaculture, College of Fisheries and Ocean Sciences, University of the Philippines Visayas, 2011-04)
Effect of elevated carbon dioxide (CO2) and phosphorus levels on nitrogen uptake, lipid content, and growth of Tetraselmis sp. were investigated. Cultures of Tetraselmis sp. were added with CO2 and phosphorus at concentrations above those currently used in aquaculture practices in a factorial experiment. Three levels of CO2 (no addition, 5% v/v, and 10% v/v of the incoming air for aeration) and three levels of phosphorus added as NaH2PO4 (5, 10, 20 mg L’1) in modified F medium with NH4+ as the primary nitrogen source were used. Optical density (680 nm) and residual NH3-N in the culture medium were monitored daily over a culture period of 6 days. Relative growth rate (k'), nitrogen uptake (pg NH3-N cell’1 day1), and lipid content (% dry weight) were calculated and determined at the end of the culture period. No interactive effect between phosphorus and CO2 levels was observed in all variables measured (p > 0.05). Highest growth rate (k = 1.82±0.04), nitrogen uptake (0.316±0.008 μg NH3-N cell1 day1), and lipid content (10.95±0.15 %DW) were exhibited at 10% CO2 supplementation. Growth and nitrogen uptake were similar in treatments with elevated levels of phosphorus, but lipid yield (9.41±0.27 %DW) was lowest at 20 mg L1 of phosphorus supplementation (p < 0.05). These results showed the critical role of CO2 in nitrogen uptake, lipid content, and growth of Tetraselmis sp. It also indicates the potential of this algal species for waste water remediation, biofuel production, and carbon sequestration.